This invention relates to means to control the firing pattern of automatic or semi-automatic weapons so that the within-the-burst dispersion is modified in a desired manner. Burst compensators are devices attached to the muzzle of a gun to control the motion of the weapon during the firing of a burst. One type of prior art compensator comprised fixed means to vent the exhausting propellant gases in an asymmetric manner so that a force, usually downward, was exerted on the muzzle upon firing. This downward force compensated for the tendency of most hand-held weapons to climb during firing. The present invention comprises a compensator intended to be attached to the muzzle of a gun and to provide compensation which varies from round-to-round within a burst, with the result that the firing pattern can be made to oscillate around a desired aim point. The device produces burst pattern control which is independent of the gunner's firing position or of the particular gunner. For example, it is effective whether the gunner is standing or prone, or right-handed or left-handed.